Editing Nuisance parameter (section)

==Theoretical statistics==
The general treatment of nuisance parameters can be broadly similar between frequentist and Bayesian approaches to theoretical statistics. It relies on an attempt to partition the [[likelihood function]] into components representing information about the parameters of interest and information about the other (nuisance) parameters. This can involve ideas about [[Sufficiency (statistics)|sufficient statistics]] and [[ancillary statistic]]s. When this partition can be achieved it may be possible to complete a Bayesian analysis for the parameters of interest by determining their joint posterior distribution algebraically. The partition allows frequentist theory to develop general estimation approaches in the presence of nuisance parameters. If the partition cannot be achieved it may still be possible to make use of an approximate partition.

In some special cases, it is possible to formulate methods that circumvent the presences of nuisance parameters. The [[t-test]] provides a practically useful test because the test statistic does not depend on the unknown variance but only the sample variance. It is a case where use can be made of a [[pivotal quantity]]. However, in other cases no such circumvention is known.